Presentation on theme: "Listeria monocytogenes and listeriosis"— Presentation transcript:
1 Listeria monocytogenes and listeriosis Megan Antosik, RD
2 Agenda History Microbiology Related foods Infection Pathogenesis At-Risk PopulationsDiagnosis & TreatmentOutbreak HistoryCurrent OutbreaksPrevention
3 Objectives After this presentation, audience members will be able to: Identify at-risk populations for contracting Listeria monocytogenes.List 3 foods highly susceptible to contamination of Listeria monocytogenesDescribe the clinical characteristics used to diagnose and identify listeriosis.
4 History Hayem (France, 1891) & Henle (Germany, 1893) Hulphers (Sweden, 1911) assigned the name Bacillus hepatitisFrench clinicians preserved a diphtheroid isolated form of spinal fluid cultures of a patient with meningitisBacterium monocytogenes, named for the monocytosis it produced in rabbitsGellin et al 1989
5 History Lord Joseph Lister (1925) – Listerella hepatolytica Nyfeldt (1929)Listeria monocytogenes (1940)Gellin et al 1989
6 Listeria Seven species of Listeria Listeria monocytogenes Listeria ivanoviiListeria seeligeriaListeria welshimeriGellin et al 1989
7 Listeria monocytogenes Facultative anaerobeß-hemolyticGram-positiveNon-acid fastNon-sporulating linear rodCan grow at temperatures as low as 4°CIncubation period of 5-70 daysGellin et al 1989
8 L. monocytogenes Sixteen serotypes Only 3 responsible for more than 90% of human diseaseSerotype 4bSerotype 1/2bSerotype 1/2aGellin et al 1989
9 L. monocytogenes Ubiquitous in nature: Dust Soil Water Sewage Decaying vegetationAnimals can carry bacterium and transmit to foodGellin et al 1989
10 As a dietitian, what can we do? How would you protect against an invader of this magnitude??
11 Susceptible Foods Ready-to-Eat (RTE) foods Raw foods Hot dogsDelicatessen meatsSoft cheesesRaw foodsMeatFruitsVegetablesUnpasteurized foodsMilk and milk productsstatic.howstuffworks.com/gif/hot-dog-km.
16 At Risk?In the United States, an estimated 1,600 persons become seriously ill with listeriosis each year. Of these, 260 die.Older adultsPregnant womenNewbornsImmunocompromisedGeneral public
17 Manifestations Diagnosis of “invasive” listeriosis Symptoms include: HeadacheStiff neckConfusionLoss of balanceConvulsions
18 Listeriosis in Older Adults and the Immunocompromised Host-dependentSepticemiaMeningitisDeathPersons with AIDS: They are almost 300 times more likely to get listeriosis than people with normal immune systems.
19 Listeriosis in Pregnant Women Twenty times more likely to get listeriosis. About one in six (17%) cases occurs during pregnancyCommonly experience mild “flu-like” symptomsInfections:Still birthMiscarriagePremature deliveryLife-threatening Infection of the newborn
20 Diagnosis Blood Cerebrospinal fluid (CSF) Amniotic fluid No stool or serological tests available
21 Treatment Most cases can spontaneously be cleared within 7 days Otherwise - treated with IV antibioticsAmpicillinBactrim
24 What can we do? Activate Listeria Initiative USDA FSIS & FDA “Zero Tolerance” policyInitiate the Healthy People objectiveAchieve a 50% reduction in listeriosis incidence by 20102.5 cases per 1 million peopleVoetsch et al 2007
25 How do we evaluate efficacy? Active surveillance studiesFoodborne Disease Active Surveillance Network (FoodNet)Assess consumer practicesDetermine the burden of foodborne illness in the United StatesMonitor trends in the burden of specific foodborne illness over timeAttribute the burden of foodborne illness to specific foods and settingsDisseminate information that can lead to improvements in public health practice and the development of interventions to reduce the burden of foodborne illness.The network was established in July 1995 and is a collaborative program among CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration (FDA). FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut,Georgia, Maryland, Minnesota, New Mexico,Oregon, Tennessee and selected counties inCalifornia, Colorado, and New York to get reports of infections diagnosed in residents of these areas. The surveillance area includes 15% of the United States population (46 million persons).FoodNet accomplishes its work through active surveillance; surveys of laboratories, physicians, and the general population; and population-based epidemiologic studies. Information from FoodNet is used to assess the impact of food safety initiatives on the burden of foodborne illnessVoetsch et al 2007
31 Did we achieve our goals? Incidence of invasive listeriosis decreased by 24%Pregnancy-associated decreased by 37%Decrease of 23% in patients > 50 years oldCrude incidence in 2003 was 3.1 cases per 1 millionVoetsch et al 2007
36 What Went Wrong? Inspectors ignored federal regulators FDA cited “serious design flaws” and “lack of awareness”Bio Food Safety Auditing gave Jensen Farms near perfect marksJensen Farms did not have proper chlorine or anti- bacterial washImproper equipment
38 As dietitians, what can we do? Prevention methodsFood SafetyCook foods thoroughlyPrevent cross-contaminationBuy pasteurized foodsProper sanitationKnow where your food comes fromKeep up-to-date on foodborne illness outbreaksRegulation of food safety policies
39 Questions? Don’t be afraid of food! Just play it safe!